This invention relates to an apparatus for cutting a mini-blind, i.e. to an apparatus for reducing the width of a venetian blind by cutting material from an end of the blind.
Venetian mini-blinds are commonly used as a low cost solution for covering windows. In order to reduce manufacturing costs, producers of such blinds often manufacture large quantities of mini-blinds in a limited number of sizes. The standard blind sizes usually fit the standard windows in modern homes and buildings. However, frequently older homes and buildings do not have standard sized windows, and consequently the standard size of blinds will not fit such windows. The alternative for older homes and buildings is to use custom made blinds, which are substantially more expensive than standard blinds.
In an effort to reduce the cost of custom made blinds, some suppliers produce custom-sized blinds by severing the ends of standard blinds which are wider than the window over which the blind is to be installed. This has given rise to a need for an apparatus for severing of the ends of a mini-blind while providing clean high quality cut ends.
Numerous solutions have been proposed for the problem, including the devices disclosed in U.S. Pat. No. 5,339,716 to Sands et al, and Canadian Patent Application No. 2,174,800 by Marocco (published in April 1997). While both of the devices are capable of severing the end of a blind, both suffer from the disadvantage that the head rail and the slates and the base rail are severed in separate cutting operations, which tends to increase the size and complexity of the cutting device. In addition, the mechanical arrangements for effecting the cutting operations tend to be complex, which increases the cost of the device and can reduce reliability. Finally the cutting operation of both devices tends to be laborious, thereby reducing the productivity of the device, that is, the rate at which blinds can be processed using the device.
An object of the present invention is to provide an apparatus for cutting a mini-blind which overcomes the above noted deficiencies.
Another object of the invention is to provide a cutting apparatus capable of producing a high quality cut end on a mini-blind, while being mechanically simple, reliable, and safe to use.
Accordingly, the present invention provides an apparatus for cutting a mini-blind of the type having a head rail, a bottom rail, and a plurality of slats. The apparatus includes a frame defined by a base and a pair of opposed end walls, and a mini-blind receiving and severing area proximate one of the end walls. A drive screw is operatively supported by the end walls and extends therebetween. A carriage is slidably disposed on the base for substantially linear movement between the end walls, the carriage being in threaded engagement with the drive screw, whereby the carriage can be driven along the length of the base by rotation of the drive screw. A knife is removably attached to the carriage for severing an end of a mini-blind as the carriage is advanced through the blind receiving and severing area of the frame. A mandrel is removably connected to an end wall and extends into the blind receiving and severing area of the frame, the mandrel being capable of receiving and supporting the head rail of the mini-blind, and inhibiting movement and/or distortion of the mini-blind during cutting. A clamp releasably clamps the mini-blind in the receiving and severing area of the frame.
Other features of the apparatus of the present invention include:
a top plate fixedly mounted on the end walls. The top plate includes an elongated, longitudinally extending slot which serves as a linear guide for the carriage;
an impact resistant, transparent cover fixedly mounted on the end walls, adjacent to and abutting the top plate. The cover serves to protect a user from upwardly projected debris during severing of a blind while offering a substantially unobstructed view of the severing operation. Preferably, the apparatus further includes an impact resistant, transparent front plate extending between the end walls, and extending downwardly from the cover. The front plate serves to protect a user from forwardly projected debris during severing of a blind while offering a substantially unobstructed view of the severing operation. By means of the cover and the front plate, the user is able to continuously monitor a severing operation, while being protected from flying debris. Thus a high quality cut can be ensured, and the safety of the operator is enhanced;
a gauge assembly for selectively controlling the amount of material to be severed from each end of a blind. The gauge assembly includes a gauge holder, a ruler slidably mounted on the gauge holder, and a stop bar depending from an end of the ruler. The ruler includes indices indicative of the length of material to be removed from a blind. Preferably, the indices are marked as a half-scale, such that the length indicated on the ruler corresponds to the total amount by which a blind will be shortened when material has been removed from both ends of the blind;
the gauge holder is operatively mounted on the carriage above the top plate, and includes a lock for releasably locking the ruler in a selected position. The lock includes a pressure plate movably disposed within a bore in the gauge holder, and a pressure-screw in the gauge holder for selectively pressing the pressure plate against the ruler. Friction between the ruler and the pressure plate serves to prevent unintentional movement of the ruler;
the gauge holder includes an integrally formed pointer located proximate the indices of the ruler, whereby the position of the stop bar can be accurately set by a user;
the stop bar includes an elongated free end defining an abutment surface substantially parallel to the path of movement of the carriage and located in the blind receiving and severing area of the frame. The abutment surface serves to limit the amount of material to be removed from an end of a blind. Thus, in use, the position of the abutment surface of the stop bar can be set by adjusting the ruler, with reference to the ruler indices and the pointer of the gauge holder. The position of the abutment surface of the stop bar can then be locked using the lock. Subsequently, a blind can be inserted into the blind receiving and severing area of the frame until the head rail, slats, and base rail contact the abutment surface of the stop bar, thereby ensuring that the material will be removed from the ends of all of the components of the blind. Furthermore, a substantially equal length of material can be reliably removed from the ends of a plurality of blinds, without stopping to measure prior to each severing operation. This increases production and reliability;
the knife includes a cutting edge for severing a blind within the cutting area of the frame. Preferably, the cutting edge is concave, so that the cutting edge first contacts opposite longitudinal edges of a blind during severing of the blind. This has the effect of reducing the forces required for cutting, and reduces the tendency of the blind components to twist or deform during the severing operation;
the knife includes a first side extending rearwardly from the cutting edge and substantially parallel to a direction of movement of the knife during a cutting operation. The first side can be concave for providing a curved end on a severed blind, which is visually more pleasing;
the mandrel includes at least one surface having an arcuate contour corresponding to that of the first side of the knife. Thus the cutting edge of the knife and the mandrel cooperate to provide efficient shearing of a blind as the knife is advanced through the blind receiving and severing area of the apparatus;
the knife includes a second side extending rearwardly from the cutting edge at an angle with respect to the first side to define a wedge at the leading end of the knife. The knife further includes a shoulder at the rear end of the wedge. The shoulder operatively engages an edge of the carriage to stabilize the knife, and thereby prevent undesired movement of the knife during repeated severing operations;
the drive screw is rotated by a crank handle or by a power drive system such as an electric motor;
the clamp cooperates with the mandrel to secure the head rail, slats and bottom rail of a blind as a single body within the blind receiving and severing area of the frame. The clamp includes a pin engageable with a groove in the base to limit forward movement of the clamp; and
at least in the vicinity of the blind receiving and severing area, the frame is provided with large radius fillets and bevelled edges to promote clearing of debris from the apparatus. This has the effect of making the apparatus effectively self-cleaning because debris from previous severing operations is cleared from the blind receiving and severing area by movement of the carriage. Consequently, numerous blind ends can be severed in succession without clogging or jamming the apparatus with debris.
The apparatus of the present invention is particularly suitable for severing the ends of mini-blinds constructed of PVC or similar thermoplastic material.